I have no idea if the bug has existed for a long time and I just hadn’t noticed it before, but the cadence symbol has a small graphic error. There are two small markers at the top left and bottom right that shouldn’t be visible.
ATV tvOS16, ZWIFT 1.29.0
Your eyes must be better than mine 
I´m riding 1,2m in front of a 55" TV. 
that might explain it!
The non drive side crank looks shorter too. 
You see the bike moving left to right whereas I see it moving right to left.
Still not resolved.
First world problem, I know, but it is so annoying to see this. Once discovered, I just can’t ignore it.
Still there with v1.50.2.